The rodent vestibular system is immature at birth. During the first postnatal week, vestibular type I and type II hair cells start to acquire their characteristic morphology and afferent innervation. We have studied postnatal changes in the membrane properties of type I hair cells acutely isolated from the semicircular canals (SCC) of gerbils and rats using whole cell patch clamp and report for...

Human hair follicles are miniature hair growing organs. A common human hair disorder is androgenetic alopecia (AGA), which becomes a medical problem only when the hair loss is subjectively seen as excessive, premature, and distressing on the scalp. The objectives of the present study were to culture the hair stem cells in vitro and to study the morphology of the cultured cells for the treatment...

In mammals, cochlear sensory hair cells that are responsible for hearing are postmitotic and are not replaced after loss. One of the most promising strategies to regenerate hair cells is to identify and inhibit the factors preventing the conversion of adjacent non-sensory supporting cells into hair cells. Here we demonstrate that mammalian hair cells can be directly generated from supporting ce...

The inner ear not only transduces sound-induced vibration into electrical signals, it also amplifies weak sound to boost its detection. The actuators of this active process are sensory outer hair cells in the organ of Corti, whereas the inner hair cells ensure that the sound-induced signals reach the auditory nerve. However, how the outer hair cells modulate the stimulus to the inner hair cells...

BACKGROUND In mammals, hair cells do not undergo spontaneous regeneration when they are damaged and result in permanent hearing loss. Previous studies in cultured Organ of Corti dissected from neonatal animals have shown that both DAPT (r-secretase inhibitor in the Notch signal pathway) treatment and Atoh1 overexpression can induce supernumerary hair cells. The effects of simultaneous DAPT trea...

The mechanisms that lead to the production of sensory hair cells during regeneration have been investigated by using 2 different procedures to ablate preexisting hair cells in individual neuromast sensory epithelia of the lateral line in the tails of salamanders, then monitoring the responses of surviving cells. In one series of experiments, fluorescent excitation was used to cause the phototox...

The distribution of middle-weight neurofilament protein (NF-M), an intermediate filament of neurons, was examined in the developing and mature avian inner ear by using immunocytochemical techniques. NF-M was detected in auditory hair cells and VIIIth cranial nerve neurons. NF-M-positive hair cells are first detected at embryonic day 11 (E11) in superior hair cells in the mid-proximal (mid-frequ...

Despite the fact that mammalian hair cells and neurons do not naturally regenerate in vivo, progenitor cells exist within the postnatal inner ear that can be manipulated to generate hair cells and neurons. This work reveals the differentiation capabilities of distinct inner ear progenitor populations and pinpoints cell types that can become cochlear hair cells, vestibular hair cells, neurons, a...

Cdc42 is a key regulator of dynamic actin organization. However, little is known about how Cdc42-dependent actin regulation influences steady-state actin structures in differentiated epithelia. We employed inner ear hair-cell-specific conditional knockout to analyze the role of Cdc42 in hair cells possessing highly elaborate stable actin protrusions (stereocilia). Hair cells of Atoh1-Cre;Cdc42(...

The avian basilar papilla is composed of hair and supporting cells arranged in a regular pattern in which the hair cells are surrounded and isolated from each other by supporting cell processes. This arrangement of cells, in which the apical borders of hair cells do not contact one another, may be generated by contact-mediated lateral inhibition. Little is known, however, about the way in which...